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. 2025 Aug 30;25(1):565.
doi: 10.1186/s12866-025-04289-6.

Detection and antimicrobial susceptibility of E. coli O157:H7 in the milk supply chain, milking environments and humans in Woliata Sodo, Ethiopia

Seblewengel Ayichew  1 , Ashagrie Zewdu  2 , Bekele Megersa  3 , Teshale Sori  3 , Fanta D Gutema  3   4
Affiliations

Detection and antimicrobial susceptibility of E. coli O157:H7 in the milk supply chain, milking environments and humans in Woliata Sodo, Ethiopia

Seblewengel Ayichew et al. BMC Microbiol. .

Abstract

Background: Escherichia coli O157:H7 is a strain that produces Shiga toxin, which can cause infections ranging from mild to severe in humans. Cattle are a primary reservoir for the bacteria, and the contaminated milk and milk products can transmit these bacteria to humans, posing a risk of infection. The present study aimed to evaluate the occurrence of E. coli O157:H7 and determine its antimicrobial susceptibility profile across the milk supply chain, milking environments, and humans in Woliata Sodo, Southern Ethiopia.

Methodology: A total of 644 samples, including raw milk, hand swabs, teat swabs, equipment swabs, floor swabs, and human stool, were collected through a cross sectional study. Bacterial detection was performed according to the ISO 16,654 standard method, and the antimicrobial susceptibility of the isolates was evaluated using the Kirby-Bauer disk diffusion method against 14 antimicrobials representing ten different classes.

Results: The overall detection rate of E. coli O157:H7 was 3.1% (20/644). The highest detection rate was observed in milk samples collected at milk collecting centers, at 10% (5/50). In comparison, detection rates were 6.8% (4/59) in samples from milkers' hands, 5.4% (2/37) in farm floor swabs, and 2.9% among outpatients presenting with diarrhea. All the isolates showed resistance to doxycycline, erythromycin, tetracycline, clindamycin, and vancomycin. Additionally, 95%, 90%, and 90% of isolates were resistant to amoxicillin, ampicillin, and streptomycin, respectively. Resistance was lower for ceftriaxone (20%) and chloramphenicol (15%). A significant proportion (100%) of the isolates exhibited multidrug resistance.

Conclusion: This study confirmed the presence of multidrug resistant E. coli O157:H7 in the tested sample. Notably, the highest prevalence was detected in milk samples from collection centers, underscoring post harvest contamination as a critical point of intervention. Identification of the pathogen on milkers' hands, farm floors, and human stool samples highlights potential transmission pathways and suggests a tangible risk of foodborne infections. These findings emphasize the critical need for targeted public health strategies, including comprehensive education on hygienic practices and the implementation of effective contamination control measures, to reduce the risk of infection and protect consumer health.

Keywords: Antimicrobial resistance; E. coli O157:H7; Ethiopia; Milk supply chain; Milking environment.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: of the research was obtained from the institutional ethical review committee of the Addis Ababa University, College of Veterinary Medicine (VM/ERC/17/01/12/2020) and Woliata Sodo University, SNNPRs (IRB/41/12/1223). The Research carried out on human data complies with the Helsinki Declaration, such as the samples taken from human participants conducted only by individuals with the qualified professionals. Before the study began, detailed discussions were made with the human participants about the objective of the study, methods, anticipated benefits, and potential risks, and participants were enrolled after obtaining written and verbal informed consent. Informed consent was also obtained from the animal owners to use the cows in the study to participate. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Map of Ethiopia showing Wolaita Sodo
Fig. 2
Fig. 2
Agarose gel electrophoresis of PCR products with stx2 (350 bp) primers; Lan 1:100 bp DNA Ladder; lane 2–6: positive for stx2 gene; lane7: Positive control; lane8: Negative Control
Fig. 3
Fig. 3
Agarose gel electrophoresis of PCR products with eae (490 bp) primers: Lane 1:100 bp DNA Ladder; Lane2-18: positive for eae gene; lane 19: Positive control; lane 20: Negative Control
See this image and copyright information in PMC

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References

    1. Misganaw A, Melaku Y, Tessema G, Deribew A, Deribe K, Abera S et al. National disability-adjusted life years (DALYs) for 257 diseases and injuries in Ethiopia, 1990–2015: Findings from the global burden of disease study 2015. 2017. p. 28. - PMC - PubMed
    1. Scallan Walter E, Griffin P, Bruce B, Hoekstra R. Estimating the number of illnesses caused by agents transmitted commonly through food: a scoping review. Foodborne Pathog Dis. 2021;18:841–58. - PubMed
    1. Alegbeleye O, Guimar J, Cruz A, Sant’Ana A. Hazards of a ‘healthy’ trend? An appraisal of the risks of Raw milk consumption and the potential of novel treatment technologies to serve as alternatives to pasteurization trends food sci. Technol. 2018;82:148–66.
    1. Farrokh C, Jordan K, Auvray F, Glass K, Oppegaard H, Raynaud S, Thevenot D, Condron R, De Reu K, Govaris A, Heggum K, Heyndrickx M, Hummerjohann J, Lindsay D, Miszczycha S, Moussiegt S, Verstraete K, Cerf O. Review of Shiga-toxin-producing Escherichia coli (STEC) and their significance in dairy production. Int J Food Microbiol. 2013;162(2):190–212. - PubMed
    1. Gutema F, Rasschaert G, Agga G, Jufare A, Duguma A, Abdi R. Occurrence, molecular characteristics, and antimicrobial resistance of Escherichia coli O157 in cattle, beef, and humans in Bishoftu town, central Ethiopia. Foodborne Pathog Dis. 2021;18:1–7. - PubMed

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